A study by the RCN suggested that 61,000 posts were at risk of being slashed across the health service, including nursing and other jobs, with 26,000 already lost in the two years to April.

The loss of so many jobs showed the "weakness" of government pledges to protect the front line, the organisation said ahead of its annual conference in Harrogate this week.

Community services, covering district and mental health nurses and those who visit patients in their own homes, were being "overburdened", said the RCN.

Cuts and underinvestment risked a "revolving door" for patients, who were discharged from hospital only to find there was no support in the community so had to be readmitted to hospital, it also warned.

Fewer than one in 10 of 2,600 community nurses polled by the RCN said they had enough time to meet the needs of their patients, while nine out of 10 revealed that their caseload had increased in the past year.

Dr Peter Carter, general secretary of the RCN, said: "Yet again, and despite numerous warnings, NHS organisations are making short-sighted cuts across the UK.

"Nurses are being stretched too thin, and many are approaching breaking point. Inevitably, patient care is going to suffer.

"We are now seeing a clear and worrying picture of a health service which is struggling. It is struggling to keep people out of hospital because of pressures on the community, and it is struggling to discharge them with support when they leave. Very soon, patients will be left with nowhere to turn.

"This is a revolving door for patients, but it also represents a false economy at a time when there is no money to spare. We want care to be delivered closer to home, and we want community nurses to be empowered to keep their patients out of hospital, but at the moment this shift in the way care is delivered is simply a facade, with the community struggling to cope with the workload it has now, let alone the one it faces in the future.

"This is a harsh reminder that both acute and community care are overloaded and the staffing levels are so low in both that there can be nowhere for patients to turn."

The RCN said planned job cuts included more than 400 in Greater Glasgow and Clyde, a similar number in Sandwell and West Birmingham, 675 in Blackpool and a 23% reduction in staffing numbers in South London up to 2015.

The Government was urged to take the "stark" figures seriously.

Deputy Prime Minister Nick Clegg denied that the NHS was about to "break" and said the Government did not "recognise" the figures produced by the RCN.

"We simply do not recognise them, we actually think the numbers are relatively stable," he told ITV's Daybreak.

Health Minister Simon Burns said: "We do not recognise these figures. Official statistics show that there are only 450 fewer qualified nursing staff in England than in September 2009 while the number of managers has been slashed by 15%.

"The number of nurses to beds in hospitals is going up and in 2011-12 we expect to train just over 2,300 community nurses and health visitors - double the number of places last year."

A spokeswoman for Blackpool Teaching Hospitals said the trust has not made any cuts to "frontline" staff and is not planning to in the next year.